Hi Daniel,
Next, I want to use it with Linux as kernel (linux_x86). If I try to run the resulting application, the usb_drv component throws the following error:
no route to service "Platform"
So, is it possible to compile and run the intended application without modifications?
If I want to use the linux devices (e.g. usb), who can I achieve this in code?
on base-linux, the USB driver resides in the Linux kernel. Genode's usb_drv cannot be used. However, your 'ServoController' doesn't actually need a USB driver but merely a terminal session. Your scenario relies on the usb_drv + usb_terminal in this respect. On Linux, I would use a completely different terminal service.
The best approach would be to have a Genode component - let's call it lx_terminal - that opens a character device on Linux and provides a terminal service by forwarding all 'read' and 'write' operations to the Linux device. This component could then be used with any arbitrary Linux device, on particular your USB-serial device that would normally appear at /dev/ttyUSB0.
The resulting picture would look like this:
ServoController --------------------------------- lx_terminal | -------.-----------' | | Genode -------V------------------------- /dev/ttyUSB0 Linux kernel --------------------------------- Hardware
Unfortunately, the lx_terminal component does not exist yet. But similar components for other Genode services exist, which you could use blue print:
* os/src/drivers/nic/spec/linux/ (provides a NIC session via a Linux tap device)
* os/src/server/lx_fs/ (provides a file-system session by accessing the Linux file system)
* os/src/drivers/framebuffer/spec/sdl (provides a framebuffer and input session via libSDL)
* os/src/drivers/audio/spec/linux (provides an audio-out session via ALSA)
Actually, when looking at this list, it might be even possible to emulate the lx_terminal component by combining the lx_fs with the file_terminal component (gems/src/server/file_terminal). But a dedicated lx_terminal component would certainly be nicer.
Cheers Norman
PS: In principle, it would be interesting to use Genode's device drivers on top of the Linux kernel by facilitating Linux' user-level device-driver infrastructure. This would clear the way to run your entire scenario including the USB driver on Linux. We have briefly documented this idea of "microkernelizing Linux" at http://genode.org/about/challenges#Platforms